Power transmission mechanism



5 Sheets-Sheet l Original Filed July 21, 1958 BYNORMA/v TGJENERAL A FTOFPNEVS Aug. 10, 1965 J. KNoWLEs ETAL POWER TRANSMISSION MECHANISM 5 Sheets-Sheet 2 Original Filed July 2l, 1958 INVENTORS JAMES' KNOWLES THOMAS RSTOCKTO/V B RMA NQENERA L A 77'0 RNA-'KS Aug. 10, 1965 J. KNowLEs ETAL 3,199,377

POWER TRANSMISSION MECHANISM Original Filed July 2l, 1958 5 Sheets-Sheet 3 far/Verzer Fen/ense .Se rra amr/967754 a7 d Ve IN VEN TORS JAMES KNOWLE'S THOMAS S` TOC K TON E .E d.

Aug. 10, 1965 J. KNowLl-:s ETAL 3,199,377

POWER TRANSMISSION MECHANISM Original Filed July 2l, 1958 5 Sheets-Sheet 4 nu? e /Y '55k/21 7 M 55; f ya {Zac/1167' d Veg/1,665) j;

Eads; haze? ya JNVENToRs JAMES KNOWLES "El THOMAS asma/70N BYNoRMA/v .GENERAL L .f A? '11,/ l

ATTORNEYS Aug. 10, 1965 J. KNOWLES ETAL 3,199,377

POWER TRANSMISSION MECHANISM Original Filed July 21,*1958 5 Sheets-Sheet 5 B NORMA/V TGENEPAL United States Patent O 3,199,377 PUWER TRANSMHSSION MECHANISM .llames Knowles, Bioomheld Hiils, Thomas R. Stockton, Northviiie, and Norman T. General, rchard Lake, Mich., assignors to Ford Motor Company, Dearborn, lv/iich., a corporation of Deiaware Originai application July 21, 1958, Ser. No. 749,726, now Patent No. 3,033,589, dated Apr. 2, 1963. Divided and this application Feb. 20, 1963, Ser. No. 260,010 l Claims. (Cl. 74-732) This application is a division of application Serial No. 749,726 tiled Iuly 2l, 1958, now Patent No. 3,083,589 issued April 2, 1963.

Our invention relates generally to a power transmission mechanism and more particularly to a hydrokinetic transmission that is adapted for use wi-th an engine driven vehicle, although we contemplate that it may also have a variety of other uses.

The embodirnent of our invention herein disclosed includes a multiple turbine hydrokinetic unit and a simple planetary gear unit acting in cooper-ation therewith in a novel manner to provide plural torque delivery paths from a driving shaft, such as a vehicle engine crankshaft, to a driven power output shaft or tailshaft.

The hydrokinetic unit and the gear unit are capable of jointly providing a lrelatively high over-all torque multiplication ratio during initial operation from a stalled condition, and the magnitude of this ratio decreases uniformly in accordance with the driving torque demands throughout a wide range of speed ratios. The hydrokinetic unit includes primary and secondary turbine members and a pump member disposed in iluid flow relationship in a toroidal iluid circuit. The portion of the effective torque output of the hydrokinetic portion of the assembly that is contributed by the primary turbine member is greater than the torque contributed by the secondary turbine member during operation in the lower speed ratio range. But as the speed ratio increases, the ratio of the torque transmitted by the primary turbine member to the torque contributed by the secondary turbine membe-r progressively decreases.

An overrunning clutch means is provided for establishing a driving connection between the secondary turbine member and the primary turbine member under normal forward driving conditions and for accommodating a relative overrunning motion therebetween during reverse drive and during forward drive operation in the lower speed ratio range. The primary turbine member is directly coupled to one element of the planetary gear unit and a brake mechanism is employed for anchoring another element of the gear unit to provide the necessary reaction, the remaining planetary element being connected to the power output portions of the mechanism. The combined torque of the turbines is thus transmitted lto a common element of the planetary gear unit after the one-way clutch becomes effective to establish a torque delivery path between the secondary turbine member and the primary turbine member, and this combined torque is multiplied by the gear unit to establish an increased output torque. v

After the speed ratio of the hydrokinetic unit increases, the anchored element of the gear unit is released and is synchronously clutched to the secondary turbine member, a suitable clutch assembly being provided for this purpose. The two turbine members thereafter operate as a single turbine member, the effective torque ratio of the gear unit thereafter being unity.

It is thus apparent that the transmission assembly is capable of operating in two drive ranges; namely, a low drive range in which the gear unit is effective to increase the net output torque of the assembly and a high drive range in which the torque ratio of the gear unit is unity.

Provision is made for obtaining a reverse torque delivery path by using the same gear element and converter components that are employed during forward drive. This is accomplished by forming the secondary turbine member with separate inlet and outlet sections, the ontlet section being adjustable relative to the inlet section to provide different effective blade exit angles for reverse and for forward drive conditions. The exit section may normally assume an angle which is favorable to forward driving torque delivery, and servo means are provided for adjusting the effective turbine exit angle to provide a reverse turbine torque which in turn is transmitted to the planetary gear elements. An independent brake band is provided for anchoring the primary turbine member and one element of the gear unit during reverse drive operation, and after reverse operation is completed the reverse brake may be released and the secondary turbine exit section may be readjusted so that the effective secondary turbine blade exit angle is favorable for forward torque delivery. The need for providing a separate reverse gear mechanism is thus eliminated.

Similarly, the exit section of the secondary turbine member may be adjusted during forward drive operation to the reverse torque position to obtain a zero torque shift if this is desired so that the sequential operation of the low speed brake and the direct drive clutch will be characterized by a maximum degree of smoothness. These features are common to ourcopending application SN. 749,726, now Patent No. 3,083,589, iiled July '21, 1958, of which this application is a division.

According to a feature of our instant invention, provision is made for conditioning the transmission for relatively high torque ratio operation to effect maximum acceleration. This is accomplished by forming the pump member with an adjustable blade exit section that may be adjusted to an angle which is favorable to high torque, high torus iiow operation. Suitable servo means are provided within the inner torus of the converter for effecting an appropriate adjustment of the pump blade exit section. According to a preferred arrangement, the transmission control system further includes means for conditioning the planetary gear unit for torque multiplication when maximum acceleration is desired following normal, cruising operation, and this occurs concurrently with the above-mentioned adjustment of the blade exit section of the pump member to the high acceleration position.

The provision of an improved hydrokinetic transmission mechanism having an adjustable impeller section of the type set forth above being an object of our invention, it is a further object to provide a suitable automatic control for actuating the impeller blade adjusting servo to increase the performance range of the transmission and to improve the etliciency of the converter during operation in the coupling range. An adjustment of the servo to a high torque ratio position is accompanied by an increase in the converter size factor for any given speed ratio, where size factor equals impeller speed divided by the square root of impeller torque.

It is a further object of our invention to provide a transmission mechanism embodying a novel arrangement of a multiple turbine hydrokinetic unit and a gear unit wherein the effective torque output of the hydrokinetic unit is transferred to a planetary gear unit and wherein clutch and brake means are provided for controlling the relative motion of the elements of the gear units to produce two ranges of over-all driving torque ratios.

It is a further object of our invention to provide a mechanism as set forth in the preceding object wherein 3S means are provided for effecting a smooth shift from one driving torque ratio to another.

It is a further object of our invention to provide a hydrokinetic transmission mechanism of simplified construction in which the performance is characterized by a high degree of torque ratio carry-out.

It is a further object of our invention to provide a hydrokinetic transmission mechanism of the type above set forth in which means are provided for conditioning the mechanism for hill braking during which the torque is transmitted in a reverse direction through the mechanism and readily absorbed by the engine. l a

Fur-ther objects and characteristics of our transmission mechanism will readily become apparent from the following description of a preferred embodiment of our invention and from the accompanying drawings wherein:

FIGURE 1 is a longitudinal cross sectional view of an assembly view of a preferred embodiment of our invention;

FIGURE 2 is a chart showing the vector diagram for the fiuid iiow in the hydrokinetic torque converter circuit;

FIGURES 3a and 3b show a schematic representation of the automatic controls of a transmission mechanism;

FIGURE 4 is a cross sectional subassembly view of the secondary turbine member of the hydrokinetic unit;

FIGURE 5 is a view showing an adjustable blade element of the secondary turbine member; and

FIGURE 6 is an illustration, partly in section, of the secondary turbine member as viewed in the direction of the transmission axis.

For the purpose of particularly describing a preferred embodiment of the invention, reference will first be made to the assembly view illustrated in FiGURE 1 wherein numeral 10 designates an engine crankshaft and numeral 12 designates a power output `shaft or tailshaft. The transmission mechanism used for providing multiple torque delivery paths between the crankshaft if? and the tailshaft 12 comprises a hydrokinetic unit generally shown at 14 and a planetary gear unit generally shown at 16. The hydrokinetic unit 14 and the gear unit 16 are enclosed by a housing 1S which may be connected in the usual fashion to the engine block of a vehicle engine. By preference the housing 18 is constructed in one piece and, as will `subsequently become apparent, it may be formed with reduced dimensions by reason of the unique physical arrangement of the elements of the mechanism.

The crankshaft 10 has secured thereto a drive plate 20 having a starter ring gear 22 joined to the periphery thereof in the usual fashion. The drive plate is secured by bolts 24 to cooperating fianges 26 and 23 respectively formed on a pump housing 3f) and on a housing plate 32, housing Sti and plate 32 forming a part of the hydrokinetie unit 14. The pump housing 3ft denes in part a torque converter pump 34 having radially disposed blades and inner and outer shrouds shown at 36 and 38. A primary turbine member is shown at 4t) and it includes turbine blades situated at angularly spaced locations about the axis of the transmission between an outer shroud 42 and an inner shroud 44, the entrance section for the primary turbine 40 being disposed in juxtaposed relationship with respect to the exit section of pump M. A secondary turbine member is shown at 46 and it also includes a plurality of blades disposed in angularly spaced relationship between inner and outer shrouds 43 and Sti, respectively. It is carried by a hub 52 to which the radially inward portion of the shroud 48 is joined. The hub 52 is positively splined or otherwise secured lto a sleeve 52 extending longitudinally as indicated.

Hydrokinetic unit 14 further includes a reactor S6 having radially disposed blades positioned between the exit section of secondary turbine #i6 and the entrance section of the pump 34, and it functions to alter the effective fluid entrance angle for the pump 34 in the usual fashion to produce a multiplication of the effective turbine torque. For this reason the hydrokinetic unit 14 will be referred to as a torque converter unit for purposes of the present description.

The reactor 56 includes a hub 5S supported on a oneway brake 69 which in turn forms an overrunning connection between the reactor 56 and a stationary sleeve shaft 62 which extends axially and which is fixed to an adapter plate 64. Suitable bolts 66 are provided for connecting plate 64 to a transverse partition wall 68, said wall forming a physical separation between the torque converter unit f4 and a planetary gear portion of the mechanism. The wall 68 may be secured to a cooperating shoulder on the housing f8 by suitable bolts '71B and it is recessed as shown at 72 to provide a pump chamber for a positive displacement gear pump 74. This pump 74; forms a portion of an automatic control circuit for controlling the operation of the various clutch and brake elements of the transmission mechanism herein described. The pump housing 3f? is permanently secured to a hub shaft '76 which in turn is journaled by a 4suitable bushing in the wall 68. The shaft 76 is drivably keyed or otherwise connected to a power input gear of the gear pump '74.

The inner shroud d4 of the primary turbine member if? is drivably connected to a torque transfer disc '7S extending through the radially inward region of the torque converter circuit and between the exit section of the secondary turbine t6 and the entrance section of the reactor 56. The outer periphery of disc '78 is preferably formed with an elongated splined portion as indicated to form a driving connection with shroud t4 and to facilitate assembly. The body of the disc 7d is suitably apertnred to permit free iow of iiuid throughout the torus circuit of the converter unit without interruption.

The inner portion of the disc 7S is positively splined to a sleeve shaft 8f3 which may be journaled by suitable bushings within the stationary `sleeve shaft 6?..

AS previously indicated, sleeve shaft 5d is splined to the hub 52 of the secondary turbine 46 and it is also connected to another sleeve shaft 82 suitably journaled within sleeve shaft S0 as indicated. The hub 52 of the secondary turbine 46 also dcnes an outer race for an overrunning clutch indicated at S4, said clutch forming a one-way driving connection between an inner clutch race 86 and a centrally disposed shaft 88, the latter being splined to the inner race 36. The outer shroud i2 of the primary turbine member d@ is positively connected to the inner clutch race S6 by means of a drive plate 90. The shaft 88 is end supported by suitable bushings within sleeve shaft 82 and within the bearing recess formed in housing plate 32.

The inner pump shroud 36 is of cast construction and it defines an annular cylinder 92 within which an annular piston 94 is situated, said cylinder 92 and piston 96 defining in part a fiuid pressure operated servo for adjustably positioning the blade exit section of the torque converter pump 34. The inner shroud construction includes a portion 96 extending through the converter torus circuit in a radially inward direction thereby forming a connection between the inner pump shroud itself and an annular sealing ring identified at 98. The sealing ring 98 is received within a circular recess formed in pump shroud 33 and it defines therewith a radial passage Miti which communicates with a groove 102 formed in stator shaft 62 through ports in hub shaft 76. Suitable internal passages are provided for introducing fluid pressure into groove 102 when appropriate, said passages forming a part of the automatic control circuit shown in FIGURES 3a and 3b. The portion 96 has formed therein a passage MP4 extending from radial passage 100 to the annular cylinder 92 and 'is adapted to distribute working pressure to the piston 94. The blades for pump 34 may be cast integrally with the shroud 36 and the .shroud 38 may be formed with suitable depressions as shown which cooperate with periphcral projections on the pump blades to secure the blades and the inner shroud in place.

The exit section of the pump 34 includes a plurality of blade elements 196 carried by mounting pins 108 which are mounted for rotation about a generally radial axis. One blade element 106 may be situated within each of the fluid ow passages deiined by the generally radially situated pump blades for the pump 3d. it is tierefore apparent that when the blade elements 1116 are adjusted from one angular position to another, the effective pump blade exit angles will be altered. This adjustment of the blade elements 106 is accomplished by means of a mechanical connection between the piston 94 and the pins 1118, said mechanical connection comprising an oset pin portion suitably connected as indicated to the annular piston 9d. When the piston 94 is moved in a longitudinal direction, the pins 163 and the associated blade elements 1% will be angularly adjusted around their respective axes.

As previously mentioned, the exit section of the secondary turbine 45 is adjustable to provide variations in the effective blade exit angle of the secondary turbine, and this adjustment is accomplished by means of a servo mechanism including a servo cylinder member 110 having a radial ange 112 which in turn is bolted to the hub 52 of the secondary turbine member, suitable bolts 11d being provided for this purpose. A servo cylinder closure wall is formed by a disc 116 which is carried by the aforementioned sleeve 54. A suitable disc washer may be provided as indicated between the disc 116 and the torque transfer disc 7S. The cylinder member 11) and the sleeve 54 cooperate to define an annular working space within which an annular piston 118 is situated, the piston being adapted to be adjusted in a longitudinal direction. A working chamber is defined by the piston 11S and the closure disc 116 and the fluid pressure may be admitted thereto through a port 129 formed in sleeve 54 and the communicating port 122 formed in shaft 83, said port forming a portion of the automatic control circuit for the transmission. The inner periphery of the outer shroud i8 for the secondary turbine 4d forms a radial flange and it is disposed between the hub 52 and the cylinder member 11b.

A plurality of radial pins 124 is situated adjacent the exit section of the secondary turbine member and journaled in the inner shroud 19 and in cooperating openings formed in the cylinder member 11i?. Each pin 124i carries a blade element 126, and these blade elements are disposed relatively close to the reactor member 56. The angular position of the pins 124; and the blade elements 126 may be adjusted about radial axes, and this is accomplished by means of a mechanical connection between piston 113 and an offset portion 12% located at the radially inward end of pins 124. The offset portions 128 cooperate with a circular groove formed in the piston 118. This groove is defined preferably by a recess 1313 and by cooperating retainer ring 132 held in place by a suitable snap ring as indicated. It is thus apparent that when fluid pressure is admitted into the working chamber between the piston 118 and the closure disc 116, the piston 11S will be moved axially thereby rotatably adjusting the pins 124 to alter the effective secondary turbine exit angle. 1t is contemplated that a torque reversal may be obtained when the magnitude of the torus ilow velocity is within a predetermined operating range and when the blades 126 are adjusted to a reverse torque position. This reverse torque may be utilized, as will subsequently be explained, to obtain a reverse drive. lt is further contemplated that when the blades 126 are adjusted to the other extreme position, the secondary turbine member 46 will be conditioned for a positive torque delivery for etfecting forward drive operation.

Sleeve shaft 89 has formed thereon a radially extending flange 13d which has secured thereto a brake drum 136. A reverse brake band 13S encircles drum 136, and it may be applied by a fluid pressure operated servo in a conventional manner to anchor sleeve shaft 8).

The shaft 88 is drivably connected to a ring gear 140 of the planetary gear unit 16 by means of a drive member 142. A planetary sun gear is shown at 144 and it is situated in driving engagement with planet gears 146 suitably journaled on the carrier identified by numeral 143. T he carrier 1h18 is in turn secured to a power output shaft 15@ for accommodating the transmission of driving torque from the carrier to driven portions of the mechanism.

A brake drum is shown at 152 and it includes an inwardly dispose-d axial extension 15d which may be rotatably journaled on a telescopically associated extension of a supporting member 156 which in turn may be secured by bolts 153 to the rearward portion of the transmission housing 18. Extension 154 has secured thereto the sun gear 144- and additional support may be provided for the sun gear 14dand extension 154 by journaling the same on the power output shaft 151B.

A friction brake band 16@ surrounds the brake drum 1S?. and it is adapted to be energized by means of a uid pressure operated servo by anchoring the brake drum 152 and the associated sun gear 144. The drum 152 and extension 154 cooperate to define an annular Working chamber 162 within which is slidably situated an annular piston 1/4, said piston and cylinder cooperating to define a uid pressure chamber. A piston return spring is shown at 166 and it is adapted to lact on the piston 164, a suitable spring seat 16S being secured to extension 154 by a suitable snap ring to provide a seat for the spring 165. A multiple disc clutch assembly is shown at 179 and it is eifective to provide a driving connection between brake drum 152 and clutch member 172 the latter being externally splined to provide a driving connection between alternate discs of the clutch assembly 17?l and the brake drum 1512 being internally splined for accommodating the other discs of the assembly 170. The clutch member 172 is connected to torque transfer member 174 which in turn is drivably connected to a drive member 176, the latter in turn being secured to sleeve shaft til.l It is thus apparent that the clutch assembly 17@ may be energized by the piston 15d as the associated working chamber is pressurized to provide a driving connection between sleeve shaft S?, and sun gear 14d.

A positive displacement pump is generally indicated by numeral 17S and it comprises a gear member 180 drivably coupled to power output shaft 151i and situated within a pump chamber dened in part by closure plate 182 secured to a cooperating shoulder formed on the housing 18 by bolts 15S. The pump 173, together with the previously described front pump shown at 72 and 74, forms a portion of the automatic control circuit for the basic transmission structure.

A tailshaft housing 1554.- is secured to housing 18 by bolts 186, and it is adapted to enclose a tailshaft friction brake generally designated by numeral 1118. The brake 188 includes a relatively stationary casing 190 secured to the housing 18 by bolts 192 and a multiple disc brake assembly is provided as shown at 194 for anchoring the shaft 151B to the casing 19t?, said shaft and casing being appropriately splined to accommodate alternately spaced discs of the assembly 194. Casing 1% defines an annular cylinder with in which an annular piston 195 is situated, said piston being adapted to energize .the multiple brake disc assembly.

Referring next to FIGURES 5 and 6, the blade elements 126 of the secondary turbine exit section are secured in a suitable fashion, such as by projection Welding, to a flat 1% formed on pine 124 at a location intermediate the radially inward and outward ends thereof, the radially outward end of pins 124 being received through cooperating openings formed in the inner shroud 50 to provide a support for the same. One pin 12d may be situated in substantial alignment with the exit of each of the blades of the primary section of the secondary turbine 46. The blade elements 126 may be adjusted as illustrated in FIG- URE from a first position which is designated by dotted lines to a second position which is designated by full lines.

The blade elements 126 dene in part an extension of the fluid flow channels in the secondary turbine assembly and they function tol adjust the effective blade exit yangle approximately 90. If it is assumed that the secondary turbine assembly is rotating in the direction of the arrow in FIGURE 5, the direction of the exit uid velocity vector will be changed so that it will have a forwardly directed tangential component rather than a tangential component which extends in a backward direction. As will subsequently be explained in more particular detail with reference tothe vector diagrams of FIGURE 2, this reversal in the exit liuid velocity vector will result in a reversal of the effective torque acting on the secondary turbine which may be utilized to obtain reverse drive operation. rThe cooperating edges of the blade elements of the primary section of the secondary turbine 46 and the adjustable blade elements 126 are designed so that they are in substantial alignment with a minimum of clearance therebetween when the blade elements 126 assume either of the two positions shown in FIGURE 5.

Operation of the transmission yassembly of FIGURE 1 The transmission mechanism of the instant disclosure is capable of providing a relatively high over-all starting turque ratio and a smooth transition from this initial torque ratio to an over-all normal cruising ratio of unity. The planetary gear unit 16 is capable of providing either of two gear ratios during an operating shift sequence. Driving power is delivered from the engine crankshaft 1i) to the torque converter pump 3d and toroidal fluid circulation is thereby established which causes driving torque to be imparted to primary turbine member dit. If the transmission is operated from a standing start, the magnitude tof the torque acting on primary turbine member 4t) is of a substantial degree relative to the pump torque and the direction of the torus dow vectors is such that the primary turbine 4@ tends to rotate in the same direction as the pump 34. The blade angularity of the primary turbine 4@ and the secondary turbine 46, however, is such that the toroidal fluid circulation establishes a negative moment of momentum in the region of the secondary turbine 46 under these initial starting conditions and the secondary turbine 46 will therefore tend to rotate in a direction opposite to the direction of rotation of the pump 34 and primary turbine 4t?. The uid flow relationship of the primary and secondary turbines is such that the reverse driving torque of the secondary turbine will prevail until the over-all speed ratio reaches a value of approximately 0.3.

During these starting conditions, the friction brake band 16) and the disc clutch assembly 17@ are both simultaneously energized and this causes the sun gear 144 to be anchored so that it may serve as a reaction member for the planetary gear unit 16. The multiple disc clutch assembly 171i serves to `anchor the secondary turbine d6 since it partly defines a connection between the energized brake band 16@ and the secondary turbine, the other portions of the torque delivery path for the reaction torque of the secondary turbine being defined by torque transfer member 17d, drive member 1%, sleeve shaft S2 and hub 52.

The overrunning clutch 84 is inedective to anchor secondary turbine 46 against reverse rotation and it is thus necessary to utilize the multiple disc clutch 17d for this purpose if reverse rotation is to be prevented. It has been found desirable to prevent such rotation during operation in the low speed ratio range since the over-all starting torque ratio is thereby considered improved. The secondary turbine functions somewhat as a stationary torque converter reactor during this phase of the operation.

It is contemplated that the automatic control circuit will effect a disengagement of multiple disc clutch assembly 17@ after a converter speed ratio of approximately 0.3 is obtained and the torque acting on the secondary turbine i6 will thereafter be in a forward direction. The term converter speed ratio may be defined for present purposes as the ratio of the ring gear speed to the engine crankshaft speed. The overrunning clutch S4 is Itherefore effective to transfer the secondary turbine torque to shaft d8 so that the primary turbine torque will be supplemented by the torque of the secondary turbine 46. Both the primary turbine and the secondary turbine are connected to the common shaft $3 and the combined torques are then transferred through shaft d8 into ring gear 14@ of the planetary gear unit 16. The friction brake band 16@ is continually applied during this stage of the operation and the sun gear 144 therefore continues to serve as. a reaction member. This stage of the operation will hereinafter be referred to as the intermediate speed range. Y

To effect high speed operation, the multiple disc clutch assembly 17@ may againbe applied in synchronism with the disengagement of the brake band 169 and the planetary gear unit 16 therefore becomes locked-up to provide a gear ratio of unity. When a hydrokinetic coupling condition is reached, the reactor 56 overruns in a forward direction by reason of the positive torque acting thereon, the one-way brake 6i) permitting such an overrunning motion.

To obtain high performance operation of the hydrokinetic portion of the mechanism, the servo defined by the annular cylinder 92 and piston 94 may be actuated to position adjustably the blade elements 106 at the exit section of the blade elements of the pump 34. This produces a higher torque ratio in the hydrokinetic portion of the mechanism although the etiiciency is necessarily reduced.

To obtain hill braking during coasting operation, the brake band 1e@ may be energized to provide a reaction for the sun gear 144 and this causes the ring gear 14) to overspin the power output shaft. This in turn causes the primary turbine 40 to overspin. There is, therefore, a desired amount of hydrokinetic braking to provide the necessary deceleration of the vehicle. The multiple disc brake assembly 194 may be energized under these conditions by pressurizing the annular working chamber behind the piston 195. This mechanical braking action may be controlled by the automatic control circuit in a manner which will subsequently be explained. Provision is made during the operation of the brake assembly 194 for supplying the discs with a sufficient amount of cooling oil to prevent overheating. To obtain reverse drive operation, reverse brake band 138 may be energized and the friction brake band 16th may be de-energized. Also, the multiple disc clutch assembly 17d is energized to establish a connection between the sun gear 144 and the torque transfer tomber 174, the latter being connected to the secondary turbine member 46. In addition, the working chamber defined by the annular piston 118 and the cylinder member 11@ is pressurized to effect a shifting movement of the blade elements 126 of the secondary turbine member d6. This, as previously mentioned, produces a reverse torque on the secondary turbine member 46 and this reverse torque is transferred through sleeve shaft 32 and through the energized multiple disc clutch assembly 17) to the sun gear 144. The secondary turbine member therefore drives the sun gear 144 in a reverse direction, and since the reverse brake band 138 is energized, as previously explained, the carrier 14d and the associated power output shaft 15h are driven in a reverse direction,

Referring next to the vector representations of FIG- URE 2, the fluid ow relationship between the various components of the hydrokinetic portion of the mechanism is illustrated vectorially. rThe vector diagrams of FIGURE 2 represent the motion of a particle of fluid in the hydrokinetic torus circuit at the exit of each of the converter components. A separate diagram is shown for the stalled condition and for a speed ratio of 0.5 under forward driving conditions. Similarly, vector diagrams are provided for the stalled condition during reverse drive and at a speed ratio of 0.5 during reverse drive. The tangential velocity vector of a point on the various blade elements is represented by the symbol U and the fluid iiow velocity component along the blade is represented by the symbol W, the latter being at an angle equal to the angle of the blade elements. The resulting absolute velocity Vector is represented in each instance by the symbol V and the vector F represents the uid flow through the torus circuit in a direction normal to the plane of rotation of the blade elements. The angles of the inlet and exit sections of the various blade elements in the circuit are indicated and this is the preferred geometry although it is possible that deviations may be made therefrom depending upon the performance characteristics which are desired. ln the case of the stator exit vectors, the vector component U is absent since the stator is anchored against rotation during the converter phase of the operation and the absolute velocity vector is equal to and coincident with the vector representing the fiow -along the blade. The torus flow velocity decreases from a maximum at stall to a lesser value at 0.5 speed ratio in both forward and reverse driving ranges and this in turn results in corresponding decrease in the absolute fluid tiow velocity although the direction of the fluid velocity vector remains unchanged.

In the vector diagram for the pump or impeller, the absolute oW velocity vector W is the resultant of the vectors U and V. During forward drive the torus low velocity vector decreases from a maximum at stall to a lesser value at 0.5 speed ratio and a similar decrease occurs during reverse drive, `the eiect of this change on the magnitude or" the absolute flow velocity being relatively minor. The exit section of the impeller blade elements may be shifted to the performance position designated in FIGURE 2 and this alters the angle of the Vector W. Typical pump blade exit angles are illustrated in HGURE 2. However, this change in the direction of vector W has only a minor effect on the vector V since the vector U is substantially increased due to the resulting increase in the pump speed.

The vector diagram for the iirst turbine exit illustrates the eect of changes in speed ratio upon the absolute veiocity vector V as the speed ratio changes. It may be observed that as the speed ratio changes from a stalled condition to 0.5 speed ratio during forward drive, the

vector V changes form a backward direction to a forward direction; and as the angularity of the vector V approaches the angularity of the corresponding Vector for the impeller exit, the primary turbine torque approaches zero. This is true since the moment of momentum of the iiuid which enters the first turbine is equal to the moment of momentum of the fluid leaving the impeller blades and if the change in :the moment of momentum for -a particle of fluid passing through the irst turbine approaches Zero, the turbine torque will also approach zero. For purposes of discussion, the moment of momentum of a particle of iiuid in the torus circuit can be defined as the mass of that particle multiplied by the tangential component of the absolute velocity vector V multiplied by the radial distance of that particle of uid from the axis of rotation.

During reverse drive the primary turbine is anchored by reverse brake band 138 and, accordingly, the vector U is lacking in the vector diagrams for reverse operation. it is thus seen that the only change in the absolute velocity vector for the first turbine during reverse drive as the speed ratio changes from zero to 0.5 is due to the change in the magnitude of the torus flow velocity.

Referring next to the vector diagrams for the second turbine exit, it is seen that the angularity of the absolute velocity vector changes rather rapidly as the speed ratio changes. This can be observed by comparing the vector diagram for stall with the vector diagram for 0.5 speed ratio during forward drive wherein the vector V changes rom an angle of approximately to an angle of approximately 95.

The moment of momentum of a particle of iuid leaving the rst turbine is equal to the moment of momentum of a particle of iiuid entering the second turbine and the change in these quantities is a measure of the torque acting on the second turbine. It should be noted that the absolute velocity vector for a stalled condition for forward drive range is substantially equal in magnitude and direction as the corresponding vector for the first turbine. However, since the exit section of the second turbine is situated at a radius which is smaller than the operating radius of the second turbine entrance, a change in the moment of momentum of a particle of fluid passing through the secondary turbine for a stalled condition in the forward drive range is accomplished. It is thus apparent that torque will be imparted to the second turbine in a reverse direction and the second turbine will thus tend to turn in a reverse direction when the converter is conditioned for forward drive and when it is operated at speed ratios near zero. However, as previously explained, the secondary turbine is anchored by the simultaneous engagement of the multiple disc clutch 17) and the friction brake band to prevent such reverse rotation.

It should be further noted that when a speed ratio of 0.5 is obtained during foward drive operation the absolute velocity vector for the first turbine exit and the second turbine entrance will have experienced a substantial change in angularity and the tangential component of the velocity vector will have changed from a reverse direction to a forward direction. it is this change in angularity which results in a change in the direction in which the moment of momentum Operates.l As previously explained, the multiple disc clutch assembly i7@ is de-energized to permit this positive torque of the transmission to be transferred through the overrunning clutch 84 so that it will be added to the torque contributed by the rst turbine.

Referring next to the exit velocity vectors for the second turbine during reverse drive, it is apparent that the angularity of vector W has been changed from an angle greater than 90 to an angle less than 90 by reason of the adjustment of the secondary turbine exit blade elements 126 by the associated servo mechanism described in connection with FIGURES l and 5. Referring more particularly to the vector representing the stalled condition for reverse drive range, the tangential component of the absolute velocity vector at the primary turbine exit or the secondary turbine entrance has a negative sense so that the change in the moment of momentum of a particle of fluid passing through the second turbine will be very substantial. Since it is negative in character, the secondary turbine tends to rotate in a reverse direction. However, as the speed ratio increases during reverse drive, the angularity of the absolute velocity vector for the secondary turbine exit changes rapidly so that it tends to become aligned with the absolute velocity vector for the primary turbine exit or the secondary turbine entrance. The resulting decrease in the change in moment of momentum for a particie of uid passing through the secondary turbine is quite large. In the particular embodiment herein described, the absolute numerical ratio of the secondary turbine speed to pump speed during reverse drive is substantially less than the normal cruising speed ratio during direct forward drive.

Description of the automatic control circuit of FIGURES 3a and 3b It is contemplated that the shift sequences previously described may take place automatically in accordance with the operating road requirements. In the particular circuit herein disclosed a dual driving range feature is incorporated, although other schematic arrangements may also be employed which do not incorporate such a dual driving range feature but which do embody other characteristics.

During operation in the first forward driving range, the multiple disc clutch assembly i7@ is continuously energized and the friction brake band toil is energized during operation from a standing start until a direct drive is accomplished. The control circuit includes an automatic shift valve responsive to engine throttle setting and to vehicle speed to tie-energize the friction brake band tot? when a high speed cruising condition is obtained. This arrangement provides a high degree of smoothness during acceleration from a standing start although it is not the most desirable arrangement from a performance standpoint in certain speed ratio ranges since the simultaneous actuation of the multipie disc clutch assembly i7@ and the friction brake band i6@ causes the secondary turbine member 46 to remain stationary. At certain speed ratios in the intermediate range the angularity of the blade elements for the secondary turbine member 46 may be unfavorable with respect to the angularity of the absolute fluid velocity ectors in the torus circuit when the secondary turbine is stationary.

The control mechanism as illustrated in the circuit of FIGURES 3a and 3b is also capable of operating in a second drive range in which the multiple disc clutch 17d and the friction brake band 160 may be operated sequentially to provide both an intermediate gear ratio and a high speed gear ratio of unity. The multiple disc clutch assembly lll'i and friction brake band i6@ are each simultaneously energized between zero speed ratio and approximately O.3 speed ratio, as previously mentioned, in order to obtain the most desirable performance during the initial stages of acceleration from a standing start.

The control circuit of FIGURES 3a and 3b includes the aforementioned engine driven pump 74 and tailshaft driven pump 17S, both of which cooperate to provide a source of control pressure for the circuit. The reverse brake band 138 is energized by a i'luid pressure operated servo 195 which includes a piston 198 acting within a cooperating cylinder, a suitable linkage mechanism Zitti being provided for transferring the servo forces to the brake band. The piston E98 is urged to a brake release position by return spring 292.

A second brake servo is provided at 204 for operating the low speed friction brake band 160 and it includes a uid pressure operated piston 206 situated within a servo cylinder, the piston and cylinder for the servo 204 cooperating to deiine opposed pressure chambers on the opposite sides of the piston 2%. A piston return spring is provided at 2% ior normally urging the piston to a brake de-energized position. Suitable force transmitting means are provided as indicated between the piston 266 and the friction brake band i60.

The fluid pressure operated servo for the multiple disc clutch assembly 170 was previously described in connection with FIGURE 1, and it wi-ll be referred to generally in the subsequent description of the control circuit by numeral 210.

A main regulator valve is shown in FIGURE 3a at 212 and it includes .a multiple land valve spool having spaced valve lands 214, 216 and t28. The region of the main regulator valve between valve lands 214 and 216 communicates with control pressure passage 220 which in turn is connected to control pressure passage 222 extending tothe discharge side of the tailshaft driven pump The regulator valve element is biased in a downward direction as indicated in FIGURE 3a by a valve spring 228 and this spring force is opposed by a Huid pressure force acting ou a. Valve plunger 230 which is adapted to engage the lower end of the regulator valve element. Valve plunger 230 is pressurized by means of a branch passage 232.

The discharge side of pump 74 communicates with plunger 230 through a one-way check valve 234 and a second one-way check valve 236 is situated as indicated in FIGURE 3b between the discharge side of the tailshaft driven pump 173 tand passage 222. When the vehicle is operating at low vehicle :speeds .and when the vehicle is stopped with the engine running, the discharge pressure of the tailshaft driven pump y178 is either zero or is reduced in magnitude relative to the discharge pressure for pump 74. It is thus apparent that check valve 236 will be closed under these conditions and check valve 234 will be open because of diiferential pressure. Fluid pressure thus is entirely supplied by the pump 74 through passages 22@ and 22d. The valve land 216 will block communication between passage 220 and exhaust passage 225 under these conditions and the valve land 218 provides necessary pressure regulation by appropriately controlling the degree of communication between passage 224 and exhaust passage 226, the balanced forces acting on the regulator valve being provided by spring 228 and spring pressure force on plunger 230.

After the vehicle speed begins to increase, the tailshaft driven pump pressure increases relative to the pump discharge pressure of pump 7d and under certain conditions it will exceed the discharge pressure for pump 74. For example, during coasting or during a push start the check valve 23d will close and check valve 236 will be opened, and the rear tailshaft driven pump 178 will then `form the pressure source for the control circuit. Under these conditions the valve land 216 provides the necessary pressure regulation 'by controlling the degree of communication between passage 220 and exhaust passage 22e and this resul-ts in a shifting movement of the valve spool in an -upwar-d direction. The discharge from pump 74 is thereafter passed directly from passage 224- into the exhaust passage 226 since Valve land 218 is moved to au inoperative position. Pump 74 therefore operates under a minimum pressure thus reducing pumping horsepower loss and increasing the over-all mechanical eiciency.

An operator controlled manual valve is shown at 238 `and it includes a valve spool with spaced valve land 240 and 242 slidably disposed in a cooperating valve chamber. The portion of the valve chamber between valve lands 240 and 242 communicates directly with control pressure passage 222 by another control pressure passage 244;. As schematically illustrated, the valve element for the manual valve `23S may be adjusted to either of tive operating positions designated in FIGURE 3a by the symbols R, N, D, Ds and L which respectively correspond to a reverse drive range position, a neutral position, a rst drive range position, a second drive range position and a hill brake position. v

The position of the various valve elements illustrated in FIGURES 3a and 3b correspond to the first drive range position in which the multiple disc clutch assembly 17) is engaged continuously throughout the shift sequence as the vehicle accelerates from a standing start to a steady state cruising condition. The servo 2l@ for the multiple disc clutch assembly I7@ is pressurized by means of a passage 246, a hill hold valve 243, a passage 25d, a shuttle valve 252, passage 2512i and passage 256, the latter communicating with the pressurized portion of the manual valve chamber. The hill hold valve 248 includes a multiple land valve spool 258 which is spring urged in a lefthand direction as viewed in FIGURE 3b, and when it is in the position shown it provides free communication between passages 246 and 250: The aforementioned shuttle valve 252 includes a single valve plunger 25th and it is urged in a left-hand direction as indicated during operi3 lation in the first drive range under the influence of control pressure to permit free communication between passages 254 and 254i.

A low servo shift valve is generally identified by numeral 262 and it includes `a multiple land valve spool 264 and a valve plunger 266. The plunger' 266 and the valve spool 264 are situated in separate portions of a cooperatin-g valve chamber which are separated by a separating element 268. A force transmitting stem 27d is interposed between the plunger Z and the valve element 264 and it is adapted to slide freely in `a `separating element 268. The valve 264 includes three spaced valve lands 272, 274 and 276 and it is urged in a left-hand direction by a valve spring as indicated.

During operation in the low speed ratio range while the manual valve is in the iirst drive range position, the valve element 264 and plunger 266 will assume a lefthand position under the influence of the valve spring and Comunication is thus established between passage 25d and passage Ild, the latter extending to the apply side of the low speed servo 264. An orifice control valve 23d is situated in passage `2% and partly defines passage 27?. The orifice control valve 23h includes a valve element having spaced valve lands that are urged normally in a downward direction by an associated valve spring. But when the valve element assumes the position shown, free communication is est-ablished therethrough. When the orifice control valve element assumes a downward position, a rst branch portion 282 of the passage 27d is blocked by the upper valve land and a second branch passage portion 234 is uncovered by the lower valve land, the latter branch passage portion having a liow restricting orifice 285. It is thus apparent that free communication through the orifice control valve is interrupted and a fluid iiow restriction is introduced in the passage 27d when the valve element therefor is moved in a downward direction.

The orice control valve is subjected to a pressure signal which is sensitive to engine throttle movement and this pressure signal, which will hereinafter be referred to as throttle pressure, acts on the lower end of the orifice control valve element and normally biases the same in an upward direction whenever the same is under torque. This same throttle pressure acts on the differential pressure areas of spaced valve lands 272 and 274 of the low servo shift valve 262 to urge the same in a lefthand direction to supplement the action of the low servo shift spring.

The valve actuating forces acting on the low servo shift valve element 262 in the left-hand direction are opposed by a vehicle speed sensitive pressure signal acting on the left end of valve plunger 266. This speed signal hereinafter will be referred to as` governor pressure and the portion of the circuit which produces this governor pressure, as well as the portion of the circuit which produces the throttle pressure, will subsequently be fully explained.

At stall and at lower vehicle speeds, the low servo shift valve element will assume a left-hand position and free communication will be established between passage 254 and passage 273. The low speed servo will thus become energir/Jed. The transmission is then conditioned for acceleration from a standing start since both the multiple disc clutch assembly 174i and the low speed servo 264 are simultaneously energized. When the vehicle speed increases, the magnitude of the governor pressure force will correspondingly increase and at a certain shift point the valve element 264 will be urged in a right-hand direction as viewed in FIGURE 3a. The apply side of the low speed servo 204 will then be exhausted through passage 27S and through an exhaust port in the low servo shift valve chamber. The multiple disc clutch assembly 17d continues to be energized following this shift and the transmission will thereafter operate in a cruising, direct drive ratio.

A throttle valve mechanism is generally designated in FIGURE 3u by numeral 23S and it includes a valve spool 2% having spaced valve lands thereon and a hollow valve element 2%. Another valve element 294 is telescopically received Within valve element 262. A valve spring 296 is interposed between valve elements 292 and 294 and a snap ring 298 is provided for limiting the amount of relative movement between the two valve elements. Another valve spring is interposed between valve element 2% and valve spool 2%. The valve element 292 is connected to the engine throttle by a suitable mechanical linkage so that the engine throttle will cause a corresponding movement of the valve element 292. When the engine throttle is advanced, spring 3d@ becomes compressed and the biasing force acting on valve spring 2% is correspondingly increased.

The valve chamber for valve spool 2% communicates with control pressure passage 244 by means of passage 3&2 and a throttle pressure passage also communicates with the chamber for the valve spool 29d at a location intermediate the spaced valve lands. The valve spool 29'@ controls the degree of communication between passages .'iiil and 3h41 so that the biasing forces acting in a right-hand direction on the valve spool 29h will tend to c increase the degree of communication between passages 392 and 394 thereby tending to increase the magnitude of the resulting throttle pressure in passage 3de. Throttle pressure also is caused to act on the right-hand side of valve element 290 and, if desired, a suitable secondary valve spring may be provided at that location. The force of the throttle pressure acting on the right side of the spool valve 29h thus balances the biasing force of spring 3643. f

The throttle pressure thus produced in passage 3h41 is conducted to the low servo shift valve and the orifice control valve as previously explained.

Throttle pressure is also conducted to a main shift valve generally designated by numeral 3%. This main shift valve comprises a multiple land valve lspool 303 slidably situated in a cooperating valve chamber. The valve spool 368 is biased in a left-hand direction as shown in FGURE 3b by valve springs 3l@ and 3U.. A throttle pressure modulator valve element 3M is situated at one end of the shift valve chamber and the aforementioned valve spring 332 acts directly thereon to urge the same in a right-hand direction. Throttle pressure is caused to act on the right side of plunger 3M and when the shifted valve spool 3% is in a left-hand position, the valve element 314 operates to regulate communication between passage 394 and a modulated throttle pressure passage 3io, said passage 316 communicating with the righthand side of the valve chamber for valve spool 3d@ within which springs Sli@ and ST2 are situated. Modulated throttle pressure also is caused to act on a differential area formed by valve lands 318 and 329 on the valve spool 3d@ for urging the latter in a left-hand direction. When the manual valve assumes the first drive range position as illustrated, control pressure does not communicate with the valve chamber for valve spool 3% and the main shift valve is inoperative although it may be caused to shift under the influence of the opposing forces established by the modulated throttle pressure and by the governor pressure. Governor pressure is caused to act on the left end of valve spool 36S thereby establishing a pressure force which is proportional to vehicle speed and which acts on the shift valve spool in a righthand direction.

Governor pressure is obtained in the particular embodiment herein disclosed by means of the tailshaft driven pump i713, although it is contemplated that other governor pressure sources may also be used. The pump 178 is formed with two working regions, one of which pressurizes control pressure passage 222 and the other of which pressurizes a governor pressure passage 322.

The by-pass passage 324 interconnects governor pressure passage 322 and the transmission sump and it contains a fio restricting orifice 326. The orifice 326 is capable of creating a back pressure in passage 322 which is a measure of pump speed. Passage 322 in turn communicates with the passage 328 which delivers governor pressure to the left side of the low servo shift valve 2162 and the main shift valve 3%, as previously mentioned, to provide the necessary vehicle speed signal for establishing shift points.

A compensator valve is shown in FIGURE 3u at 33t) and it is capable of appropriately modifying the operating control pressure level in accordance with vehicle speed and engine torque. Compensator valve 33t) includes a valve spool 332 operating in a cooperating valve chamber and a compensator valve spring 334 is situated in the valve chamber for biasing the valve spool 332 in a right-hand direction as viewed in FlGURE 3a. Control pressure is distributed to the compensator valve chamber through a branch passage 336 at a location intermediate valve lands 338 and 34@ on the compensator valve spool 332.. A compensator pressure passage 342 communicates with the compensator valve chamber at a location adjacent valve land 34@ and it extends to the main regulator valve 212 at a location adjacent valve land 2id. The compensator pressure in passage 34.2 is capable of exerting an upwardly directed force on the main regulator valve spool in opposition to the force of spring Valve land 349 of the compensator valve controls the degree of communication between branch passage 336 and compensator passage 342.

Throttle pressure is distributed to the right-hand side of the valve spool 332 through the passage 343 which communicates with passage 3M- through a low boost valve generally identified by numeral 344. This valve 34d will be subsequently described. Also, governor pressure is distributed to the compensator valve chamber on the left side of the valve spool 332 by means of a passage 345 which communicates with the previously mentioned governor passage 328 through the low boost valve The throttle pressure and governor pressure therefore establish opposed forces which inuence the degree of communication between passages 336 and 343 that is provided by valve land 340. An annular working area is formed on the valve spool 332 at the right-hand side of valve land 34st? and compensator pressure passage 342 therefore establishes a valve biasing force which tends to reduce the degree of communication between passages 336 and 342. The force differential produced by the gov- `ernor pressure and by the throttle pressure, the force of the spring 228 and the valve biasing force of the compensator pressure produce a balanced force system and it is thus apparent that the magnitude of the compensator pressure in passage 342 will be a function of both engine throttle setting and vehicle speed. For example, if the vehicle speed should increase for any given engine throttle setting, the degree of communication between passages 336 and 342 will increase thereby increasing the compensator pressure force acting on the lower end of the main regulator valve spool. This tends to decrease the magnitude of the control pressure in the circuit which in turn reduces the capacity of the uid pressure operated servos to a value which is commensurate with the reduced torque requirements. It is pointed out that an increase in vehicle speed for any fixed engine throttlel setting is tantamount to an increase in the over-al1 speed ratio and to a decrease in over-al1 torque ratio. The relationship between speed ratio and torque ratio can be readily calculated.

Conversely, if the engine throttle setting is increased for any given vehicle speed, the compensator pressure will be decreased and the compensator pressure force acting on the main regulator valve spool will also be decreased. This produces an increase in the operating control pressure and the capacity of the transmission servos is correspondingly increased to accommodate the ini@ creased torque requirements which accompany the adjusted engine throttle setting.

It is undesirable to allow the compensator pressure to become increased for any given throttle setting after a certain limiting speed is obtained. Otherwise, the operating control pressure will be reduced at high cruising speeds to a value which is insuiiicient to maintain the required torque capacity of the transmission servos. For this reason a governor pressure cut-out feature is provided in the compensator valve and this includes the valve plug 3% situated adjacent the compensator valve spool 34? and it is provided with spaced valve lands for dehning a differential working area 34th, said working area being in fluid communication with branch passage 336 so that yit is subjected to line pressure. The liuid pressure force of the line pressure is opposed by a pressure force established by governor pressure, the latter acting on the right-hand side of valve plug 346. A spacer element 35@ is movably disposed between valve spool 332 and valve plug 336.

During operation of the transmission at lower vehicle speeds, the governor pressure is insuiicient to establish a force on valve plug 34e which will overcome the opposing pressure force of the line pressure acting thereon and the valve plug 346 will be urged in a right-hand direction so that it is inoperative. However, as vehicle speed increases for any given throttle setting, a point is reached at which the governor pressure will overcome the opposing force of the control pressure acting on valve plug 346 and the plug 34o will be urged in a left-hand direction. The force diierential acting on the plug 346 will then be transferred directly to the valve spool 332 through the spacer element 35i. The area of plug 346 upon which governor pressure acts is equal to the area of the valve spool 332 on which the governor pressure acts and further increases in governor pressure will create balanced and opposed forces on the valve spool 332. The compensator valve will thereafter be insensitive to changes in vehicle speed and further changes in control pressure below a safe minimum value will therefore not occur.

Let it now be assumed that the manual valve 23S is adjusted to the second drive range position Ds. A passage 352 will then be uncovered by valve land 242 and the exhaust port in the manual valve chamber, through which passage 352 was previously exhausted, is now closed by valve land 242. Passage 352 will therefore be subjected to control pressure and it distributes this control pressure to a communicating passage 354 which extends to the main shift valve chamber. Passage 352 also extends to a passage 35d which in turn communicates with the left end of the valve spool for a blocker vaive 353. The right hand end of the valve spool for blocker valve 353 is also subjected to line pressure by means of passage 36@ which in turn communicates with the previously described pressurized passage 254. A blocker valve spring is disposed on the left side of the blocker valve spool and when passage 356 is pressurized, the valve spring urges the blocker valve spool in a right-hand direction. When this occurs communication is established through the blocker valve by the governor pressure passage 328 and the passage 3462, the latter extending to the left-hand side of valve spool 258 for the hill hold valve 243. During operation in the first drive range position, the blocker valve is maintained in a left-hand position under the iniuence of control pressure acting on the right-hand side thereof and the passage 362 is 4Continuously exhausted through an exhaust port associated with the blocker valve chamber.

The hili hold valve is comprised of three spaced valve lands identied by numerals 3645, 366 and 368 and it is urged in a left-hand direction by a valve spring 37d. lt is thus apparent that the valve biasing force established by the governor pressure will oppose the spring biasing torce and when the governor pressure exceeds a calculated value, the hill hold valve spool will shift in a righthand direction so that valve land 364 will block passage 25) and thereby establish communication between passages 246 and the passage 3?2 between the spaced valve lands 364 and 3&5. Passage 372. in turn extends to the iluid pressure chamber on the release side of the piston 2&6 of the low speed servo 284i. Passage 372 also communicates with the manual shift valve chamber at a location between spaced valve lands 374 and 376 on the main shift valve spool.

Passage 362 is also in communication with the hill hold valve chamber adjacent the valve land 368 and when the hill hold valve spool is shifted in a right-hand direction under the influence of governor pressure, the differential area provided by valve lands 35u13 and 36S is subjected to governor pressure and a snap action occurs whereby the hill hold valve spool is shifted quickly in a right-hand direction as soon as valve land 368 uncovers the associated branch portion of passage 362.

During operation in the second drive range, control pressure is conducted to the right-hand end of the low servo shift valve spool 26d and to the right-hand end of valve plunger 266. Valve spool 26d is therefore shifted in a left-hand direction, thereby establishing Huid communication between passage 254 and passage 278. Valve plunger 265 remains inoperative since the governor pressure is insuicient to overcome the opposing force of the line pressure acting on plunger 2da. lt is thus apparent that the low servo shift valve remains in a left-hand position during operation in the second drive range and is insensitive to changes in vehicle speed.

lf it is now assumed that the vehicle is operated from a standing start with the manual valve adjusted to the Ds position, the servo Zlt and the apply side of the brake servo 264 will be simultaneously energized during the initial stage of the shift sequence thereby providing for maximum torque multiplication in the hydroltinetic portion of the transmission mechanism, The release side of the servo 25M is exhausted through passage 372 and through a communicating passage 37S which extends to an exhaust port located in the main shift valve chamber. After' the vehicle begins to accelerate, the governor pressure will urge the hill hold valve spool in a right-hand direction against the opposing force of the spring 37d to establish communication between passage 246 and passage 372, and the clutch servo 2l@ is therefore exhausted through the hill hold valve and through passage 372, passage 373 and the main shift valve exhaust port. Simultaneously with this shifting movement of the hill hold valve spool, valve land 26d blocks passage 25h. The transmission is tuus conditioned for an intermediate driving torque ratio and both the primary and secondary turbines are operative to deliver torque to the ring gear 14d of the planetary gear unit lo, the torque of the primary turbine being transferred to the secondary turbine through the overrunning clutch as previously explained. The low speed friction brake band loll continues to anchor the sun gear ldd of the planetary gear unit le to provide the necessary torque reaction.

When the vehicle continues to accelerate during operation in the second drive range for an given engine throttle setting, the governor pressure will ultimately increase to a value which will be suillcient to urge the main shift valve spool in a right-hand direction against the opposing force of valve spring 33t@ and the modulated throttle pressure forces acting on the main shift valve spool. This position of the main shift valve spool is illustrated in FlGURE 3b, and when it is in this position communication is established between passage 3514 and passage 378 and the main shift valve exhaust port is no longer in cornmunication with passage 37S, the release side of the low speed servo therefore being pressurized. As previously er1;- plained, the apply side of the servo Zld is also pressurized, but since the servo spring 2&5 normally urges the piston to a retracted position, the low speed servo becomes released under spring pressure.

Since passage 372 communicates with passage 246 through the up-shifted hill hold valve element, the passage 246 and the clutch servo Zltl. become pressurized following an up-shift of the main shift valve element and the planetary gear unit lo therefore assumes a locked-up condition. The transmission is thus conditioned for cruising, direct drive operation.

If hill braking is desired, the manual valve may be shifted to the L position and this causes the passage 378 to become uncovered by manual valve land 242 and the associated exhaust port for passage 378 is simultaneously closed by this same valve land. Passage 378 communicates with passage 3% which in turn communicates with a passage 3%2 through the throttle valve chamber, a suitable groove 334 being provided in the valve element 2%2 for this purpose. Line pressure is thus conducted to the left-hand side of the blocker valve generally shown at 386, thereby shitting the same in a right-hand direction against the opposing force of a blocker valve spring. The blocker valve thereby blocks passage 352. The passage 372 establishes communication between passage 25d and passage 352 so that the latter continues to be pressurized with control pressure. Passage 352 also extends to the main shift valve chamber and distributes control pressure to the right end of the main shift valve spool and to the differential area provided for the valve lands 31S and 32@ to shift the main shift valve spool in a lett-hand downshift position. Communication is thus established between passage and a passage 3S@ which in turn extends to the left-hand side of the low boost valve T44 to urge the latter against an opposing spring force to a righthand position. This interrupts communication between passages 328 and 345 and simultaneously exhausts passages Sdtl and 345 through the associated exhaust port. In addition, the low boost valve establishes communication between passage 342 and a converter pressure passage 396, said passage 39@ extending to the interior of the hydroliinetic torus circuit. When the low boost valve is shifted in the right-hand direction in this fashion, the governor pressure acting on the left-hand side of the compensator valve spool is exhausted and the throttle pressure which acts on the right-hand side of the compensator valve spool is replaced by a relatively high converter pressure. Both of these pressure changes result in an increased biasing effect on the compensator valve spool in a left-hand direction which tends to decrease the degree of communication between passages 33o and 342, and this in turnresults in a decreased compensator pressure. This decreased compensator pressure in turn results in an increased control pressure in the circuit and the capacity of the brake servo 2M accordingly will be increased. The increased line pressure will prevent slippage during a coasting operation and although the friction brake band loll is self-energizing for torque delivery during normal forward driving, the brake capacity is still suilcient during delivery of torque in a reverse direction during coast even though the self-energizing feature of the brake band is lacking.

lt is thus apparent that the release side of the low speed seivo 294 will be exhausted througth the main shift valve exhaust port and that the low speed servo will become applied. This anchors the sun gear of the planetary gear unit lo to cause an overspeeding of the ring gear Mtl the primary turbine member itl.

The blocker valve 35S continues to establish communication between passages 32S and 362 to distribute governor pressure to the left-hand side of the valve spool of hill hold valve 24S and when the main shift valve is downshifted as above described, the clutch servo 21) -is exhausted through the passage 246, through the hill hold valve and through passages 372 and 378, the latter communicating with the main shift valve exhaust port. As deceleration continues to a point where the governor pressure is insufllcient to maintain the hill hold valve in the 11p-shift position, the hill hold valve spool will be shifted to the position shown in Fit-GUE 3b and the clutch servo 21d will again be energized so that both the servos 2li? and 204 are simultaneously energized. The secondary turbine member @te is anchored during this stage of the brakin o eration. hlildditioial 1hill braking may be obtained by the multiple disc brake assembly 19d. The automatic controls for this brake assembly includes a retarder activator valve 392 which comprises a simple valve spool biased .in one direction by a valve spring and in another direction by throttle pressure which is distributed thereto by a passage 3de. When the valve spool for the retarder .activator valve 392 assumes the position shown, communication is established between the aforementioned passage 25d and a passage 31%. However, during a coasting operation the throttle valve pressure drops to zero and the retarder activator valve spool assumes a right-hand position, thereby connecting the aforementioned governor pressure passage 328 with passage 394. Passage 394 in turnextends to one side of a retarder clutch valve, identied by numeral 396, which comprises a simple valve spool normally urged in a left-hand direction by an associated valve spring. A line pressure passage 39S communicates with the valve chamber associated with the retarder brake valve spool and when the valve spool is positioned as shown in FiGURE 3b, the passage 3598 is blocked. However, when the retarder brake valve spool assumes a lefthand position, passage 3% communicates with a passage 40d.

During normal driving operation, the throttle pressure is sufficient to maintain the retarder activator valve spool in a left-hand position and the retarder Ibrake valve is thus continuously urged in a right-hand position under the influence of control pressure. During coasting, however, the retarder activator valve will move under spring pressure in a right-hand direction thereby pressurizing the retarder brake valve spool with governor pressure rather than control pressure. At relatively high speeds the governor pressure is sufficient to maintain the retarder brake valve in the position shown. But after the vehicle accelerates below a calculated speed, the retarder brake valve will shift in a left-hand position thereby establishing communication between line pressure passage 393 and passage 469, the latter in turn extending to the retarder brake disc lubrication jets 402. When the retarder brake valve spool is shifted in this fashion in a left-hand direcf tion, communication is established between a passage and a passage 4de, the latter extending to the servo for the brake assembly 194 which is partly defined by piston 195. Passage 404 is pressurized with the modulated retarder pressure obtained by means of a retarder pressure regulator valve identified 4by numeral 403. Valve 498 comprises a valve spool operating in an associated valve chamber which communicates with control pressure passage 254. The retarder regulator valve spool is urged in a right-hand direction by valve spring dit? and the biasing eort of valve spring 410 tends to increase the degree of communication between passage 254 and passage 404. The right side of the retarder regulator valve spool is in communication with passage 4M so that the spring force is opposed by the modulator pressure force in passage ddd. It is thus apparent that the magnitude of the modulated pressure made available to the multiple disc retarder brake assembly 19d will be determined by the calibration of the retarder regulator valve.

If a forced lrickdown is desired following cruising, direct drive operation, the valve element 292 may be urged to the extreme right position by depressing the accelerator pedal which moves the engine throttle to its extreme position. When this is done a port 411.2 in the valve element 292 is brought into communication with the branch passage rtl4 extending from throttle pressure passage 304. This then admits throttle pressure into the interior of valve element 292 on one side of the associated valve element 294, suitable passages die being provided for this purpose. Continued movement of the Valve ele'- ment 292 to a downshift position will cause contact -between a shoulder 413 on the control valve body and an abutment 122 on the valve element 232e. As the valve element 292 moves further, relative movement will then take place between valve elements and 292 and this relative movement is resisted by the throttle pressure which exits in the interior of valve element 292. The vehicle operator therefore experiences what may be referred to as a iluid detent feel which permits him to deter mine readily when a downshift will be initiated. This also prevents an inadvertent downshift by the vehicle operator when it is not desired. Finally, as the valve element 292 is moved to a final position against the opposing fluid pressure force of the throttle pressure, passage 382 is brought into iuid communication with the interior of valve element 2192 and with passage 14. This occurs when a valve port 4t2@ is uncovered by the associated valve land on valve element 29d.

Simultaneously with the uncovering of port 42h, valve element 292 blocks passage 33d so that the pressurized passage 332 will not be exhausted therethrough. After the valve element 292 has assumed this ultimate position, the magnitude of the throttle pressure is equal to control pressure and this control pressure is conducted to one side of the main shift valve spool through passage 382, thereby shifting the same in a left-hand direction to effect a downshift. The release side of the brake servo 264 is exhausted through passage 372 and passage 378 after a downshift occurs and since the apply side of the servo 2nd continues to be pressurized, the brake band io@ will be energized.

Concurrently with the application of brake baud ildti, clutch servo 2id is exhausted through passage 245, through the upshifted hill hold valve 24S and through passages 372 and 373. The blocker valve 38e assumes a right-hand position during a downshift since the lefthand side of the blocker valve element is pressurized. Communication is thus established between control pressure passage 254 and control passage 352 so that the latter continues to be pressurized with control pressure.

Referring next to the adjustable pump exit feature previously mentioned, the automatic controls therefor may be seen in FIGURE 3cr and they include a first performance valve tl-24 and a second performance valve shown at L26. The servo for the adjustable blade elements litio of the pump exit section is pressurized when the blade elements are in the normal cruising position and spring means are provided for returning the bladed elements to a high performance position when the pressure is released. The selective distribution of iiuid pressure to the pump exit servo is controlled by the performance valves 424 and 426.

Referring first to valve 42d, it comprises a simple valve spool which is spring urged in an upward direction and which is urged in a downward direction by throttle pressure distributed thereto through the passage 3524. When the valve assumes an upward position communication is established between line pressure passage 244 and a passage 428 extending to the servo for the pump exit section. The lower end of the valve spool for performance valve 424 communicates with passage 33@ which is pressurized when the manual valve is shifted to the L position. When the Valve spool for performance valve 42d assumes an upward position under the iniiuence of control pressure, communication between passages 244 and 42S is established and the pump exit servo is pressurized. The pump may be conditioned for high performance by increasing the engine throttle setting, which results in an increase in throttle pressure and this in turn causes the performance valve L24 to assume the high performance position.

The second performance valve 426 comprises a simple valve spool which is normally urged in a downward di rection by converter pressure and which is urged in an upward direction by governor pressure distributed in to the passage 323. At elatively high vehicle speeds the governor pressure is sufficiently high to move the valve spool for the second performance valve 4126 in an upward position and this causes an interruption between performance valve 424 and passage 330. Concurrently, however, control pressure passage 254 communicates with the lower end of valve 424 so that a downshift resulting from kickdown pressure cannot be accomplished at an undesirably high vehicle speed. The converter pressure passage 3% may be regulated by a simple converter pressure regulator valve identified by numeral 439. Valve 439 comprises a simple valve spool spring urged in an upward direction against the iiuid pressure force of the converter pressure acting on the upper end thereof. The balanced spring and pressure forces on the regulator valve element control communication between the line pressure passage 432 and the aforementioned converter pressure passage 39) to establish a reduced operating pressure level in the hydrokinetic torus circuit of the mechanism.

The passage 428 may extend to the interior of the converter torus circuit through an opening in one or more of the impeller blades.

FIGURE 3a shows an alternate blade adjusting servo arrangement. It comprises a Belleville spring actuator that is anchored at its inner periphery to the inner pump shroud and which is connected at its outer periphery to the adjusting cranks for the impeller exit blade elements. An annular sealing ring is provided in the interior of the inner pump shroud, and the adjusting cranks are connected to it. It may move axially as uid pressure is admitted behind the Belleville spring. rl`his will move the impeller exit blade elements to the cruising position.

A lubrication pressure regulator valve is identified by numeral 433 and it comprises a simple valve spool 4434 having spaced valve lands, one of which is adapted to control the degree of communication of line pressure passage 432 with a lubrication pressure passage 436. The valve spool 434 is urged in a left-hand direction as viewed in FGURE 4a by a valve spring 438 and this spring force is opposed by the fiuid pressure force of the lube pressure in passage 436 which is distributed to the left-hand side of valve spool 434. It is thus apparent that the regulator pressure in passage 436 will be reduced in magnitude and will be determined by the calibration of the regulator valve 433.

A valve plunger 444B is situated in the valve chamber for valve spool 434 and the valve spring 438 is seated thereon as indicated. A passage 442 communicates with the end of the valve chamber for regulator valve 433 and it also communicates with the manual valve at a location which is spaced from the valve lands 24) and 242. Passage 442 also communicates with reverse brake band servo 195 for the purpose of distributing control, pressure to one side of the piston 198.

To obtain reverse drive operation, the manual valve may be shifted to the position indicated by the symbol R and this causes the passage 442 to communicate directly with line pressure passage 244 through the spaced valve lands 24u and 242. Reverse brake servo 1% therefore becomes pressurized and control pressure is also distributed to one side of the plunger 44u of the regulator valve 442, This causes .the valve spool 444 to move in a left-hand direction to bring passages 432 into communication with passage 43e, thereby pressurizing the working chamber defined by the servo cylinder member liti) and the annular piston 118 of the secondary turbine member. The annular piston 118 is therefore shifted in a left-hand direction to rotate the blade elements 126 to a reverse position illustrated by means of full lines in FGURE 6, thereby adapting the secondary turbine for reverse torque delivery. During normal forward driving operation, the blade elements 126 are maintained in a forward driving position illustrated in FIGURE by dotted lines by reason of the torque exerted thereon by the torus flow.

When passage 442 is pressurized in this fashion, control pressure is distributed to the left side of the aforementioned shuttle valve 252, thereby blocking communication between passages 25@ and 254. This prevents uid pressure in the reverse servo from being exhausted through passage 256 which becomes uncovered by the valve land 242 of the manual valve when the manual valve spool is moved to a reverse drive position.

Passage 442 also distributes control pressure to the left-hand side of valve plug 346 of the compensator valve and the spacer element 35'@ is subjected to control pressure. The control pressure force acting on spacer element 359 is transmitted directly to the compensator valve spool 332 to oppose the governor pressure force acting on the other end of the valve spool 332. The magnitude of the compensator pressure passage 442 is thereby decreased by reason of this rearrangement of forces acting on compensator valve spool 332 and, as previously explained, this results in an increase in the magnitude of the control pressure. This increase in control pressure is necessary since the capacity of the reverse servo must be sufi'icient to accommodate a reverse driving torque.

n addition to this variation in the servo capaci-ty during reverse drive, the capacity of the low servo and the forward drive clutch servo during forward drive operation may be varied in accordance with eng-ine throttle setting upon movement of the engine lthrottle from a closed position te a setting of approximately 60% of the wide open position. The engine torque is generally proportional to throttle setting in this range of settings, but movement of the engine throttle beyond this range is not accompanied by a significant increase in engine torque. Provision therefore is made for making the throttle valve insensitive to throttle movement at increased settings and this is done by adapting the throttle valve so that abutment 522 contacts shoulder ilu when the limiting engine throttle setting is reached. Further increases in engine throttle setting therefore will not affect throttle pressure. This feature, together with the aforementioned governor pressure cutout feature in the compensator valve, insures a smooth shift under all driving conditions.

We contemplate that variations in the preferred embodiment of our invention herein disclosed will come within the scope .of our invention .as defined by the following claims.

We claim:

i. A hydrok-inetic torque converter mechanism comprising a bladed impeller member and a bladed turbine member disposed in a toroidal fluid circuit .in iiuid Yflow relationship, said impeller member having an outer torus shroud and an inner torus shroud, said turbine member being disposed in driving relationship with respect to a driven member, primary impeller blade elements disposed between said shrouds and cooperating therewith to define radial iiow passages, the flow exit section of said primary blade elements being disposed at a radially outward region of said circuit, secondary blade elements located between said shrouds adjacent said flow exit section and cooperating therewith to define continuations of said radial flow passages, servo means for adjustably positioning said secondary blade elements with respect to said primary blade elements whereby the angularity of the fluid flow impeller exit velocity vectors may be altered, said servo means comprising relatively movable parts that cooperate to dene a pressure cavity, one of said parts being connected to said inner shroud, a mechanical connection between the other servo part and said secondary blade elements, a source of a control pressure signal, passage means communicating with said control pressure signal source for distributing selectively a control pressure signal to said pressure cavity, and valve means disposed in and partly defining said passage means .and responding to changes in the speed of said driven member and in the torque applied to said impeller member for controlling distribution of said signal to said servo means.

2. A hydrokinetic torque converter mechanism comprising a bladed impeller member an da bladed turbine member disposed in a toroidal fluid circuit in fluid flow relationship, said turbine member being disposed in driving relationship with respect to a driven member, said bladed impeller member having an outer torus shroud and an inner torus shroud, primary im-peller blade elements disposed between said shrouds and cooperating therewith to define radial flow passages, the flow exit section of said primary blade elements being disposed at a radially outward region of said circuit, secondary impeller blade elements located between said shrouds adjacent said flow exit section, :an annular cylinder connected .to said inner shroud, an annular piston disposed slidably within said annular cylinder and cooperat-ing therewith to define an annular fluid pressure cavity, a mechanical connection between ea-ch secondary blade element and said annular piston, a source of a control pressure sign-al, passage means communicating with said control pressure signal source for pressurizing selectively said pressure cavity to position adjustably sai-d secondary blade elements with respect to said primary blade elements thereby altering the angularity of the absolute fluid flow velocity vectors at the flow entrance region of said turbine and increasing .the size factor of said converter as the flow exit edge of said secondary blade elements are adjusted in a direction opposite to the direction of rotation of said impeller, the size factor being equal to the impeller member speed divided by the square root of the impeller member torque, land valve means disposed in and partly defining said passage means and responding to changes in the speed of said driven member and in the torque applied to said impeller member for controlling distribution of said signal to said pressure cavity.

3. A hydrokinetic torque converter mechanism comprising a bladed impellcr member and a bladed turbine member vdisposed in a toroidal fluid circuit in fluid ilow relationship, said bladed impeller including primary blade elements that define in part radial fluid tiow passages, said turbine member being situated in driving relationship with respect to a driven member, the flow exit section of said blade elements being disposed at a radially outward region of said circuit, secondary blade elements located adjacent said flow exit section and forming a continuation of said radial ilow passages, servo means disposed within the interior of said toroidal flow circuit for -adjustably positioning said secondary blade elements with respect to said primary blade elements and including a pressure sensitive servo member mechanically connected -to said secondary blade elements, `an annular cylinder connected to said inner shroud, an annular piston disposed slidably within said .annular cylinder and cooperating therewith to define an annular fluid pressure cavity, a mechanical connection between each secondary blade element and said annular piston, a source of a control pressure signal, passage means communicating with said control pressure signal source for pressurizing selectively said pressure cavity to position adjustably said secondary blade elements with respect to said primary blade elements thereby altering the angularity of the absolute fluid flow velocity vectors at the flow entrance region of said turbine and increasing the size factor of said converter as the flow exit edge of said secondary blade elements are adjusted in a direction opposite to the direction of rotation of said impeller, the size factor being equal to impeller member speed divided by the square root of impeller member torque, and valve means responding to changes in the speed of said driven member and in the torque applied to said impeller member for controlling distribution of said signal to said pressure cavity.

d. A hydrokinetic torque converter mechanism cornprising a bladed impeller member and a bladed turbine member disposed in a toroidal fluid circuit in fluid flow relationship, said impeller member having an outer torus shroud and au inner torus shroud, said turbine member being disposed in 4driving relationship with respect to a driven member, primary impeller blade elements disposed between said shrouds and cooperating therewith to define radial fiow passages, the ow exit section of said primary blade elements being disposed at a radially outward region of said circuit, secondary blade elements located between said shrouds adjacent said flow exit section and cooperating therewith to define continuations of said radial flow passages, an annular cylinder connected to said inner shroud, an .annular piston disposed slidably within said annular cylinder and cooperating therewith to define an annular iluid pressure cavity, a mechanical connection between each secondary blade element and said annular piston, a source of a control pressure signal, passage means communicating with. said control pressure signal source for pressurizing selectively said pressure chamber to position adjustably said secondary blade elements with respect to said primary blade elements thereby altering the angularity of the yabsolute fluid flow velocity vectors at the flow entrance region of said turbine and increasing the size factor of said converter as the flow exit edge of said secondary blade elements are adjusted in a direction opposite to the direction of rotation of said impeller, the size factor being equal to the impeller member speed divided by the square root of the impeller member torque, and valve means disposed in and partly defining said passage means and including a first portion responding to changes inthe torque applied to said impeller member for controlling distribution of said signal to said pressure cavity and a portion that responds to changes in the speed of said driven member to overrule the influence of said first valve means portion.

5. A hydrokinetic torque converter mechanism comprising a bladed impeller and a bladed turbine disposed in a toroidal fluid circuit in fluid flow relationship, said bladed impeller including primary blade elements that define in part radial fluid flow passages, the flow exit section of said primary blade elements being disposed at a radially outward region of said circuit, secondary blade elements located adjacent said flow exit section and forming a continuation of said radial flow passages, servo means disposed within the interior of said toroidal flow circuit for adjustably positioning said secondary blade elements with respect to said primary blade elements and including a pressure sensitive servo member mechanically connected to said secondary blade elements, an annular cylinder connected to said inner shroud, an annular piston disposed slidably within said annular cylinder and cooperating therewith to define an annular fluid pressure cavity, a mechanical connection between each secondary blade element and said annular piston, a source of a control pressure signal, passage means communicating with said control pressure signal source for pressurizing selectively said pressure chamber to position adjustably said secondary blade elements with respect to said primary blade elements thereby altering the angularity of the absolute fluid flow velocity vectors at the flow entrance region of said turbine, and valve means disposed in and partly defining said passage means and including a first portion that responds to the torque applied to said impeller member for controlling distribution of said signal to said servo and a second portion that responds to changes in the speed of said driven member for overruling the influence of said first valve means portion, said annular piston being adapted to move axially with respect t0 the axis of said turbine and said impeller, said mechanical connection comprising a separate crank supporting each secondary blade element, one end of said crank extending radially inwardly, the radially inward end of each crank being offset with respect to the axis of adjustment of said secondary blade elements and being connected to said annular piston whereby axial adjustment of said annular piston is translated into rotary adjusting movement of said secondary blade elements, the trailing edge of the secondary blade ele- Lb ments being adjustable forwardly in the direction of rotation of sait. turbine member to establish maximum eiiiciency cruising performance operation and being adjustable rearwardly in the opposite direction to establish high torque ratio performance operation.

6. A hydroiiinetic torque converter mechanism comprising a bladed impeller member and a bladed turbine member disposed in a toroidal fluid circuit in fluid flow relationship, said impeller member having an outer torus shroud and an inner torus shroud, primary impeller blade elements disposed between said shrouds and cooperating therewith to define radial flow passages, the flow exit section of said primary blade elements being disposed at a radially outward region of said circuit, secondary blade elements located between said shrouds adjacent said ilow exit section and cooperating therewith to define continuations of said radial fiow passages, an annular cylinder connected to said inner shroud, an annuiar piston disposed slidably within said annular cylinder and cooperating therewith to define an annular fluid pressure cavity, a mechanical connection between each secondary blade element and said annular piston, a source of a control pressure signal, passage means communicating with said control pressure signal source for pressurizing selectively said pressure chamber to position adjustably said secondary blade elements with respect to said primary blade elements, and valve means disposed in and partly deiining said passage means and including a first portion that responds to changes in the torque applied to said imp-eher member for controlling distribution of said signal to said pressure cavity and a second portion that responds to changes in the speed of said driven member for overruling the influence of said first valve means portion, said mechanical connection comprising a separate crank supporting each secondary blade element, one end of each crank extending radially inwardly, the radially inward end of each crank being offset with respect to the axis of adjustment of said secondary blade elements and being connected to said annular piston whereby axial adjustment of said annular piston is translated into rotary adjusting movement of said secondary blade elements, the trailing edge of the secondary blade elements being moved forwardly in the direction of rotation of said turbine member to establish maximum efliciency cruising performance operation and being shiftable in the opposite direction to establish high torque ratio performance operation.

7. In a power transmission mechanism adapted to deliver power from a driving member to a driven member, a hydrokinetic torque converter unit comprising a bladed impeller member and a bladed turbine member disposed in a toroidal fluid circuit in fluid flow relationship, said bladed impeller member having an outer torus shroud and an inner torus shroud, primary impeller blade elements disposed between said shroud and cooperating therewith to define fiow passages, the ow exit section of said primary blade elements being disposed at a radially outward region of said circuit, secondary impeller blade elements located adjacent said ow exit section and forming continuations of said flow passages, a multiple speed ratio gear unit having gear elements that define in part a power flow path between said driving and driven members, a power input gear element connected to said turbine member and a power output gear element boing connected to said driven member, fiuid pressure responsive friction torque establishing means for controlling the relative motion of said gear elements, a control pressure source, conduit structure connecting said control pressure source and said friction torque establishing means, a shift valve means disposed in and partly defining said conduit structure for controlling distribution of pressure to said friction torque establishing means, a torque demand responsive signal pressure source, a driven member speed responsive signal pressure source, branch passages establishing communication between said shift valve means and said signal pressure sources, pressure responsive servo means disposed within said toroid-al circuit for adjustably positioning said secondary blade elements relative to said primary blade elements including a first member carried by said primary blade elements and a second pressure movable member connect-ed to said secondary blade elements, a servo feed passage extending between said control pressure source and said servo means, a pressure distributor valve means disposed in and partly defining said feed passage for establishing and interrupting a fluid connection between said servo means and said control pressure source, said distributor valve means being in communication with said torque demand responsive pressure and actuated thereby to control the operation of said servo means.

8. In a power transmission mechanism adapted to deliver power from a driving member to a driven member, a hydrokinetic torque converter unit comprising a bladed impeller member and a bladed turbine member disposed in a toroidal fluid circuit in iuid flow relationship, said bladed impeller member having an outer torus shroud and an inner torus shroud, primary impeller blade elements disposed between said shrouds and cooperating therewith to define iow passages, the iiow exit section of said primary lblade elements being disposed at a radially outward region of said circuit, secondary impeller blade elements located adjacent said flow exit section and forming continuations of said flow passages, a multiple speed ratio gear unit having gear elements that define in part a power fiow path between said driving and driven members, a power input gear element being connected to said turbine member and a power output gear element being connected to said driven member, Huid pressure responsive friction torque establishing means for controlling the relative motion of said gear elements, a control pressure source, conduit structure connecting said control pressure source and said friction torque establishing means, a shift valve means disposed in and partly defining said conduit structure for controlling distribution of pressure to said friction torque establishing means, a torque demand responsive signal pressure source, a driven member speed responsive signal pressure source, branch passages establishing communication between said shift valve means and said signal pressure sources, pressure responsive servo means disposed within said t'oroidal circuit for adjustably positioning said secondary blade elements relative to said primary blade elements including a first member carried by said primary blade elements and a second pressure movable member connected to said secondary blade elements, a servo feed passage between said control pressure source and said servo means, and a pressure distributor valve means disposed in and partly defining said feed passage for establishin-g and interrupting a fluid connection between said servo means and said control pressure source, said distributor means being in communi-cation with said torque demand responsive pressure and actuated thereby lto control the operation of said servo means, and driven member pressure signal sensitive valve means for overruling the action of said distributor valve means and disabling the same during operati-on at driven member speeds in a predetermined range of values.

9. In a power transmission mechanism adapted to deliver power from a driving member to a driven member, a hydrokinetic torque converter unit comprising a bladed impeller member an-d a bladed turbine member disposed in a toroidal uid circuit in fiuid ow relationship, said bladed impeller member having an outer torus shroud .and an inner torus shroud, primary impeller blade elements disposed between said shrouds and cooperating therewith to define flow passages, the flow exit section of said primary blade elements Vbeing dispose-d at a radially outward region of said circuit, second-ary impeller blade elements located adjacent said flow exit section and forming continuations of said flow passages, a multiple speed ratio gear unit having gear elements that define in part a power fiow path bet-Ween said driving and driven memareas?? bers, a power input gear element being connected to said turbine member and a power output gear element being connected to said driven member, fluid pressure responsive friction torque establishing means for controlling the relative motion of sa-id gear elements and conditioning the same for operation with various speed ratios, a control pressure source, conduit structure connecting said control pressure source and said friction torque establishing means, a shift valve means disposed in and partly defining said conduit structure for controlling distribution of pressure to said friction torque establishing means7 a torque demand responsive signal pressure source, a driven member speed responsive signal pressure source, branch passages establishing communication between said shift valve means and said signal pressure sources, pressure responsive servo means dispose-d within said toroidal circuit for adjustably positioning said secondary blade elements reiative to said primary blade elements including a first member carried by said primary blade elements and a second pressure movable member connected to said secondary blade elements, a servo feed passage between said control pressure source `and said servo means, said feed passage including a portion extending from the outer torus shroud to the interior of the inner torus shroud through the region lof said primary blade elements, a pressure distributor valve means disposed in and partly defining said lfeed passage for establishing and interrupting a iiuid connection between said servo means and said control pressure source, said distributor means being in com-munication with said torque demand responsive pressure and actuated thereby to control the operation of said servo means.

19. In a power transmission mechanism adapted to deliver power from a driving member to a driven member, a hydrokinetic torque converter unit comprising a bladed impeller member and a bladed turbine member disposed in a toroidal fluid circuit in fluid iow relationship, said bladed impeller member having an outer torus shroud and an inner torus shroud, primary impeller blade elements disposed between said shrouds and cooperating therewith t-o deine flow passages, the iiow exit section of said primary blade elements being disposed at a radially outward region of sai-d circuit, secondary impeller blade elements located adjacent said ow exit section and forming cont'inuations of said flow passages, a multiple speed ratio gear unit having gear elements that define in part a power flow path Ibetween said driving and driven members, a power input gear element being connected to said turbine member and a power output gear clement being connected to said driven member, fluid pressure responsive friction torque establishing means for controlling the relative motion of said gear elements, a control pressure source, conduit structure connecting said control pressure source and said friction torque establishing means, a shift valve means disposed in and partly dening said conduit structure for controlling distribution of pressure to said friction torque establishing means, a torque demand responsive signal pressure source, a driven member speed responsive signal pressure source, branch passages establishing communication between said shift Valve means and said signal pressure sources, pressure responsive servo means disposed within said toroidal circuit for adjusta-bly positioning said secondary blade elements relative to said primary blade elements including a first member carried by said primary blade elements and a second pressure movable member connected to said secondary blade elements, a serv-o feed passage between said control pressure source and said servo means, sai-d feed passage including a portion extend-ing from the outer torus shroud to the interior of the inner torus shroud through the region of said primary Vblade elements, a pressure distributor valve means disposed in and partiy ieining said feed passage `for establishing and interrupting a fluid connection between said servo means and said control pressure source, said distributor means being in communication with said torque demand responsive pressure and actuated thereby to control the operation of said servo means, and driven member pressure signal sensitive valve means for overruling the action of said distributor Valve means and disabling the same during operation at driven member speeds in a predetermined range of values.

References Cited ,by the Examiner UNTEI) STATES PATENTS DON A. WAITE, Primary Examiner. 

7. IN A POWER TRANSMISSION MECHANISM ADAPTED TO DELIVER POWER FROM A DRIVING MEMBER TO A DRIVEN MEMBER, A HYDROKINETIC TORQUE CONVERTER UNIT COMPRISING A BLADED IMPELLER MEMBER AND A BLADED TURBINE MEMBER DIPOSED IN A TOROIDAL FLUID CIRCUIT IN FLUID FLOW RELATIONSHIP, SAID BLADED IMPELLER MEMBER HAVING AN OUTER TORUS SHROUD AND AN INNER TORUS SHROUD, PRIMARY IMPELLER BLADE ELEMENTS DISPOSED BETWEEN SAID SHROUD AND COOPERATING THEREWITH TO DEFINE FLOW PASSAGES, THE FLOW EXIT SECTION OF SAID PRIMARY BLADE ELEMENTS BEING DISPOSED AT A RADIALLY OUTWARD REGION OF SAID CIRCUIT, SECONDARY IMPELLER BLADE ELEMENTS LOCATED ADJACENT SAID FLOW EXIT SECTION AND FORMING CONTINUATIONS OF SAID FLOW PASSAGES, A MULTIPLE SPEED RATIO GEAR UNIT HAVING GEAR ELEMENTS THAT DEFINE IN PART A POWER FLOW PATH BETWEEN SAID DRIVING AND DRIVEN MEMBERS, A POWER INPUT GEAR ELEMENT CONNECTED TO SAID TURBINE MEMBERS AND A POWER OUTPUT GEAR ELEMENT BEING CONNECTED TO SAID DRIVEN MEMBER, FLUID PRESSURE RESPONSIVE FRICTION TORQUE ESTABLISHING MEANS FOR CONTROLLING THE RELATIVE MOTION OF SAID GEAR ELEMENTS, A CONTROL PRESSURE SOURCE, CONDUIT STRUCTURE CONNECTING SAID CONTROL PRESSURE SOURCE AND SAID FRICTION TORQUE ESTABLISHING MEANS, A SHAFT VALVE MEANS DISPOSED IN AND PARTLY DEFINING SAID CONDUIT STRUCTURE FOR CONTROLLING DISTRIBUTION OF PRESSURE TO SAID FRICTION TORQUE ESTABLISHING MEANS, A TORQUE DEMAND RESPONSIVE SIGNAL PRESSURE SOURCE, A DRIVEN MEMBER SPEED RESPONSIVE SIGNAL PRESSURE SOUCE, BRANCH PASSAGES ESTABLISHING COMMUNICATION BETWEEN SAID SHIFT VALVE MEANS AND SAID SIGNAL PRESSURE SOURCES, PRESSURE RESPONSIVE SERVO MEANS DISPOSED WITHIN SAID TOROIDAL CIRCUIT FOR ADJUSTABLY POSITIONING SAID SECONDARY BLADE ELEMENTS RELATIVE TO SAID PRIMARY BLADE ELEMENTS INCLUDING A FIRST MEMBER CARRIED BY SAID PRIMARY BLADE ELEMENTS AND A SECOND PRESSURE MOVABLE MEMBER CONNECTED TO SAID SECONDARY BLADE ELEMENTS, A SERVO FEED PASSAGE EXTENDING BETWEEN SAID CONTROL PRESSURE SOURCE AND SAID SERVO MEANS, A PRESSURE DISTRIBUTOR VALVE MEANS DISPOSED IN AND PARTLY DEFINING SAID FEED PASSAGE FOR ESTABLISHING AND INTERRUPTING A FLUID CONNECTION BETWEEN SAID SERVO MEANS AND SAID CONTROL PRESSURE SOURCE, SAID DISTRIBUTOR VALVE MEANS BEING IN COMMUNICATION WITH SAID TORQUE DEMAND RESPONSIVE PRESSURE AND ACTUATED THEREBY TO CONTROL THE OPERATION OF SAID SERVO MEANS. 